Irfan View

I used the Tool (Irfan view) to check whether the given image is Jpeg, Progressive Jpeg, Bmp ....or not.

This tool will check the internal Header information about the images.

As a result this tool will inform the correct format by checking the inside bytes but not using the extension. Because an image may be Jpeg or bmp by extension. But we can't say that image is jpeg or bmp only by seeing the extension internally it may not be of that type.